1. Field of the Invention
The present invention relates to seat assemblies for vehicles such as commercial airplanes.
2. Background Information
Minimizing the possibility of head injuries to commercial aircraft passengers in the event of an emergency is of great concern for obvious safety reasons. In commercial aircraft, where passengers are seated one behind the other, there is a potential for a passenger's head to strike the seat in front of him in a sudden deceleration event. United States Government regulations concerned with passenger safety define a Head Impact Criterion (HIC) as follows: ##EQU1## where t.sub.1 and t.sub.2 =any two points in time during the head impact, in seconds, and
a(t)=the resultant head acceleration during the head impact, in multiples of g's.
Lower HIC values correspond to a lower severity of head impact. Current regulations call for HIC values of less than 1000 for commercial airline seats where a passenger head could contact a seat back in the preceding row.
The HIC formula reflects the fact that a very sudden deceleration of the head would have a greater adverse effect than a deceleration of the head which occurs over an increased period of time. The HIC value could be reduced by reducing peak acceleration of the head. A constant or more controlled deceleration of the head after it first contacts the seat back would be preferred to reduce HIC.
While the chance of head injury for passengers could be reduced by increasing the distance between the seats, this would also significantly reduce the amount of floor space available for seating and therefore have a significant adverse economic impact on commercial air travel.
What is needed is a seating system which reliably reduces HIC value and head impact in sudden impact events so as to prevent or minimize head injuries. Such a reduced HIC seat should ideally have little effect on aircraft interiors, cause no reduction in seating density, and preferably involve passive technology needing no triggering devices. The features which contribute to reduction in HIC value should be imperceptible to the passenger during normal operation, so as not to affect his or her comfort.
The present invention is a seat assembly for commercial aircraft or other vehicles with row seating. It has features that reduce the force of head impact in high impact, rapid deceleration events such as collisions. In a preferred embodiment, it has a commercially practical and inexpensive design, and is simple, rugged, and reliable in operation.